Ethylene polymeric compositions containing silver

ABSTRACT

SILVER-CONTAINING ETHYLENE PLOLYMERIC COMPOSITIONS SUITABLY EMPLOYED IN THE PREPARATION OF PHOTOGRAPHIC FILM AND COATINGS HIGHLY RESISTANT TO BACTERIA AND FUNGUS ARE FORMED FROM SILVER-CONTAINING AQUEOUS DISPERSIONS OF WATERINSOLUBLE, SELF-EMULSIFIABLE ETHYLENE-ALKYL ACRYLATE POLYMERS.

United States Patent 0 3,556,795 ETHYLENE POLYMERIC COMPOSITIONS CONTAINING SILVER Richard H. Hughes and Bert H. Clampitt, Overland Park,

Kans., and Harry D. Anspon, Kansas City, Mo., assignors to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware No Drawing. Filed Apr. 19, 1967, Ser. No. 631,874 Int. Cl. G03c 1/04 U.S. C]. 9661 19 Claims ABSTRACT OF THE DISCLOSURE Silver-containing ethylene polymeric compositions suitably employed in the preparation of photographic film and coatings highly resistant to bacteria and fungus are formed from silver-containing aqueous dispersions of waterinsoluble, self-emulsifiable ethylene-alkyl acrylate polymers.

BACKGROUND OF THE INVENTION This invention relates to ethylene polymeric compositions containing silver. In another aspect, this invention relates to the preparation of photographic film from aqueous dispersions of silver-containing water-insoluble, but selfemulsifiable ethylene-alkyl acrylate polymers. In yet another aspect, this invention relates to the preparation of coatings resistant to bacteria and fungus employing aqueous dispersions of silver-containing Water-insoluble, but self-emulsifiable ethylene-alkyl acrylate polymers.

Photography is a process of producing a visible image upon a surface by the action of light or other radiant energy. The term light as hereafter employed includes invisible radiation such as ultraviolet and infrared as well as visible light. The surface is made sensitive to light by impregnating it or coating it with a material which either changes its appearance when acted upon by light or undergoes a change which can be made visible by chemical or heat treatment.

The photographic surface is conventionally prepared 'by coating a substrate such as glass, Celluloid-type plastic or paper with a photographic emulsion comprising, for example, a gelatin-silver halide emulsion. The coated substrate or photographic film is exposed to radiant energy in a camera or other suitable device with the radiant energy producing an invisible image. This latent image is trans formed into a visible image by the action of a developer which selectively reduces exposed silver halide to silver at a much faster rate than it reduces unexposed silver halide. The image is then fixed by treating it with a solution which either dissolves out the unreduced silver halide or converts it into amaterial which is relatively insensitive to light. The image so obtained is a negative.

The photographic film produced by this conventional process contains grains or particles of silver halide deposited upon the surface. These grains or particles ad versely effect the quality of the produced photographic image. The larger grains or particles the poorer the image with the grains causing blemishes to appear on the image. To prevent the occurrence of large silver halide grains on the surface of the photographic film, extreme care must be taken during the step of precipitating the silver halide crystals in preparation of the gelatin-silver halide emulsion.

Another disadvantage of conventional photographic films is that the films are water-sensitive. Therefore, pre cautionary measures must be taken to insure that the prepared films are not exposed to water or to relatively humid atmospheric conditions.

3,556,795 Patented Jan. 19, 197I STATEMENT OF THE INVENTION -An object of this invention is to provide a novel silverethylene polymer composition and process therefor.

Another object of this invention is to provide a thermoplastic material highly resistant to fungus and bacteria.

Yet another object of this invention is to provide an improved photographic film.

Other objects, advantages and features of this invention will be readily apparent to those skilled in the art from the following description and appendant claims.

By the invention, silver-containing ethylene polymeric compositions are formed, in a first embodiment, by admixing an aqueous dispersion of a Water-insoluble, selfemulsifiable ethylene-alkyl acrylate polymer and a nitrogenous base solution of a silver salt. A film or coating material can be cast directly from the resultant aqueous dispersion.

In a second embodiment of the invention a nitrogenous base solution of a silver salt is contacted with a strongly acidic cation exchange resin under conditions such that silver ions are deposited upon the exchanged resin. An aqueous dispersion of a water-insoluble, but self-emulsifiable ethylene-alkyl acrylate polymer is contacted in the presence of a nitrogenous base with the ion exchange resin charged with silver ions. An ethylene-alkyl acrylate polymeric film or coating can be cast directly from the aqueous dispersion recovered from the ion exchange zone.

Unsupported films cast from the silver-containing, water-insoluble, self-emulsifiable ethylene-alkyl acrylate polymeric dispersions of this invention can be employed as photographic films, or in the alternative, the films can be cast upon a conventional photographic film substrate such as heretofore named and the coated substrate employed as a photographic film. Photographic films so prepared have an advantage over conventional photographic film in being water insensitive. Furthermore, the surface of the films so prepared do not contain silver halide crystals or grains and are thus superior to conventionally prepared photographic films.

Surfaces coated with the silver-containing ethylene-alkyl acrylate polymers of this invention exhibit excellent resistance to baceteria and fungussThus, the silver-containing ethylene-alkyl acrylate polymeric dispersions of this invention can be employed to surface-coat conventional substrate material so as to inhibit the attack of bacteria or fungus upon the substrate. An additional distinguishing advantage of the silver-containing films of the invention over conventional silver-containing films is that the films of the invention are heat scalable. Thus, the commercial application of such films is substantially increased by their ability to be heat sealed to themselves as well as to various substrates such as paper, aluminum foil, polyethylene, glass cotton textiles, and nylon film.

DESCRIPTION OF THE INVENTION Aqueous dispersions of self-emulsifiable, water-insoluble ethylene-alkyl acrylate polymers containing 0.01 to about 0.5 mol of acrylate groups per mol of contained ethylene groups and wherein at least a portion of the acrylate groups is in carboxylate form, are employed in preparing the silver-containing aqueous dispersions of the invention. Ethylene groups and acrylate groups as used herein are defined as those units of a polymer which correspond to the ethylene and acrylate monomers, respectively, which are polymerized in forming the polymer.

Water-insoluble as used herein refers to the inability of a fused solid ethylene-alkyl acrylate polymer to become substantially dissolved in water as measured, for example, by preparing a /2 mil cast film of the product polymer by conventional methods, placing a 10 x 10 centimeter sample in one liter of water maintained at a temperature of 30 C. for a period of 24 hours, removing the film from the water, drying the film to a constant weight of 120 C. and determining that the weight loss in the film when compared to the Weight of the original film sample shall be less than weight percent. Self-emulsifiable as used herein refers to that property of the polymer whereby one gram of the polymer in particulate form can be readily dispersed in 100 ml. of water in a stirred metal autoclave maintained at a temperature in the range of 180 to 300 C. to provide, in the absence of an emulsifying agent, a shelf-stable aqueous dispersion wherein the average particle size is less than two microns.

The ethylene-alkyl acrylate polymers employed in preparing the silver-containing compositions of this invention can be viewed generally as a polyethylene chain containing units (a) and units (b) as hereinafter defined and, optionally one of the hereafter defined following units (c) and units (d).

wherein R is selected from the group consisting of hydrogen and hydrocarbon groups, R is selected from the group consisting of hydrogen and alkali metal cations, R and R are independently selected from the group consisting of hydrogen, hydrocarbon groups, and hydroxy alkyl groups, and R is a hydrocarbon group. The mol concentration of the total of units (b), (c) and (d) is in the range of 0.01 to about 0.5 (preferably from about 0.025 to 0.25) mol per mol of contained ethylene. At least 10 mol percent of the acrylate groups of the water-insoluble, but self-emulsifiable ethylene-alkyl acrylate polymer employed in preparation of the silver-containing aqueous dispersions of this invention are in carboxylate salt form.

Copending application Ser. No. 131,108, by Jack Hurst and Harry D. Anspon, filed Aug. 14, 1961, describes the preparation of aqueous dispersions of water-insoluble, self-emulsifiable ethylene-alkyl acrylate interpolymers which are applicable in preparation of the silver-containing compositions of this invention. As described therein a selfemulsifiable portion of the acrylate groups of an ethylene-alkyl acrylate interpolymer is hydrolyzed by employing an alkali hydroxide and, optionally, a nitrogenous base. Reference is made to copending application Ser. No. 131,108 for a complete description of a suitable method of preparing aqueous dispersions of water-insoluble, selfemulsifiable ethylene-alkyl acrylate polymers to be employed in the preparation of the silver-containing compositions of this invention.

In the first embodiment of the invention, a nitrogenous solution of a silver salt is formed and the nitrogenous solution of the silver salt admixed with an aqueous dispersion of the above-described water-insoluble, self-emulsifiable ethylene-alkyl acrylate polymer. The silver salt employed may be inorganic or organic. Although not to be limited thereto, the silver salts found applicable in the preparation of the silver-containing compositions include silver chloride, silver sulfate, silver nitrate, silver acetate, silver fluoride, silver phosphate, and silver chromate with the silver nitrate and silver acetate salts preferred.

The nitrogenous base employed in preparation of the solution of the silver salt is selected from the group consisting of ammonia and amines. Suitable amines include primary and secondary amines and diamines. Illustratively, ethylene diamine and lower monoand di-alkyl substituted amines such as methylamine, ethylamine, isopropylamine, diethylamine, ethanolamine, octylarnine, and the like can be employed. A preferred nitrogenous base solvent is ammonium hydroxide.

The nitrogenous base solution containing silver is normally admixed with the aqueous dispersion of the ethylene-alkyl acrylate interpolymer such that the mol concentration of silver in the admixture does not exceed the mol concentration of carboxylic and carboxylate salt groups present in the interpolymer. It is to be understood that the concentration of silver can vary widely and will be dependent upon the use for which the product composition is being prepared, the concentration of polymer, and the concentration of carboxylic and carboxylate groups in the ethylene interpolymer. It has been observed that large excesses of silver ion concentration will increase the tendency of the aqueous dispersion to gel. Preferably, the concentration of silver in the aqueous dispersion is below that which will substantially reduce the shelf stability of the aqueous polymeric dispersion. Shelf-stable as applied to the aqueous dispersions of this invention described aqueous dispersions which give no appearance of significant change after 48 hours standing and customarily even after 30 days storage in a conventional glass container at ambient room temperatures.

A typical formulation employed in the preparation of a shelf-stable, silver-containing aqueous dispersion of this invention comprises:

6.0 ml. of a 0.1 molar silver nitrate aqueous solution,

6.0 ml. of aqueous ammonium hydroxide (concentrated),

35.0 ml. of an aqueous dispersion of a water-insoluble,

self-emulsifiable ethylene-methyl acrylate polymer containing 22.0 Weight percent solids and wherein the concentration of acrylate groups comprises 20 weight percent of the polymer.

The silver-containing aqueous dispersions of this invention can be employed in the coating of conventional substrates or in the preparation of film employing conventional processes known in the art. A suitable method of preparing a film comprises casting the film from an aqueous dispersion on a substrate such as a glass plate and curing the cast film at an elevated temperature, such as C., in an oven.

Films cast from the silver-containing aqueous disper- SlOIlS can suitably be employed in the preparation of photographic film. It is above noted that the photographic films cast from the aqueous dispersion can be unsupported or can be placed upon conventional photographic film substrates such as glass, Celluloid-coated paper or plastic material. The coated substrate or photographic film is exposed to radiant energy in a camera or other suitable device with the radiant energy producing an invisible image upon the film.

This latent image is transferred into a visible image by the action of a conventional developer which selectively reduces the exposed silver salt groups to silver at a faster rate than it reduces the unexposed silver salt groups. The image is then fixed by treating it with ammonia thereby making the film relatively insensitive to light. Conventional fixing agents were found to be ineffective and the ability of ammonia to fix latent images was found to be unique.

In a second embodiment of the invention, an aqueous dispersion of the water-insoluble, self-emulsifiable ethylene-alkyl acrylate polymer is contacted in the presence of a nitrogenous base with an ion exchange medium comprising a strongly acidic cation exchange resin charged with silver ions. Silver ions are exchanged for the alkali metal cations of the aqueous dispersion and a stable aqueous silver-containing dispersion is recovered from the ion exchange zone.

The ion exchange medium employed in preparation of the silver-containing aqueous dispersions of the invention comprises a strongly acidic cation exchange resin, preferably in particulate form, charged with silver ions. Suitable strongly acidic exchange resins include conventional sulfonated polystyrene resins such as the resins manufactured and distributed by Dow Chemical Company under the trade name of Dowex-SO. The ion exchange medium can be prepared by contacting the strongly acidic cation exchange resin with a nitrogenous base solution of the silver salt. The ion exchange resin charged with alkali metal ions can be regenerated by contacting the resin with a nitrogenous base solution of the silver salt.

Typically, the ion exchange resin charged with silver ions is placed in a vertical column and the mixture of the nitrogenous base and aqueous dispersion of the ethylene polymer passed downwardly through the column. An aqueous silver-containing dispersion of the ethylene polymer is withdrawn from the bottom of the column.

It would appear that the silver in the aqueous dispersion recovered from the ion exchange Zone is present in the polymer chain. There is evidence that the silver contained in the product obtained by practice of the first embodiment is present as the silver ion (Example VIII).

The following examples are presented to illustrate the objects and advantages of the invention. It is not intended that the invention should be limited to the specific embodiments presented herein.

EXAMPLE I In this example the bacteria and fungus resistance of the silver-containing polymeric coatings of this invention are demonstrated. The silver-containing polymeric coatings are compared with coatings prepared employing copper, zinc, mercury and lead salts. In each run two grams of salt are dissolved in ml. of water with ml. of a 58 weight percent ammonium hydroxide aqueous solution added to the salt solution. The resultant solution is then admixed with 350 ml. of an aqueous dispersion of a water-insoluble, self-emulsifiable ethylene-methyl acrylate polymer wherein 50.0 weight percent of the acrylate groups are in sodium salt form, 35.0 mol percent of the acrylate groups are in amide form, 101 mol percent of the acrylate groups are in acid form and 5.0 mol percent of the acrylate groups are in ester form. The ethylenemethyl acrylate copolymer contains 20.0 weight percent methyl acrylate and the ethylene polymer aqueous dispersion contains 20.0 weight percent solids.

For each salt wood is coated with the prepared aqueous dispersions by dipping 20 wood tongue depressers into each prepared aqueous dispersion for a period of 24 hours. Following the 24-hour period, the tongue depressers are removed from each of the aqueous dispersions and 50 percent of the tongue depressers from each salt system are dried in an oven maintained at a temperature of 150 C. The remaining 50 percent of the tongue depressers from each salt system are air dried.

Five tongue depressers from each of the above-defined groups are washed for four hours in Water and then air dried. Each of the prepared coated tongue depressers is placed in the ground containing soil bacteria and fungus for a period of six weeks. In addition to the salt coated tongue depressers, tongue depressers containing only a coating of the above-described ethylene-methyl acrylate copolymer are also placed in the ground. After six weeks all of the ethylene-methyl acrylate copolymer coated tongue depressers fail (the tongue depressers disappear). The results obtained from observation of the tongue de pressers coated with the salt systems are as shown below in Table I.

TABLE I Acetate, Nitrate, Sulfate, percent percent percent failures failures failures Room temperature cured:

100 100 100 60 100 80 100 40 20 0. even cured and soaked in water:

Copper. 100 100 '100 Zinc 80 100 100 100 100 After the tongue depressers have been in the ground for a period of nine weeks the following results presented below in Table II are observed.

TABLE II Acetate, Nitrate, Sulfate, percent percent percent failures failures failures Room temperature cured:

100 Silver. 80 20 60 150 C. oven cured:

100 100 100 100 100 100 100 60 60 60 Room temperature cured and soaked in water:

Copper 100 100 I00 Zinc 100 100 100 Mercury... 100 100 100 Lead 100 Silver 100 20 60 EXAMPLE II In this example the effectiveness of the silver-containing ethylene polymeric compositions of this invention as employed in photography is illustrated. The following formulation is prepared: 6.0 ml. of a 0.1 molar silver nitrate aqueous solution is combined with 6.0 ml. of ammonium hydroxide (concentrated); to the admixture is added 35 ml. of the water-insoluble, self-emulsifiable ethylene-methyl acrylate aqueous dispersion of Example I.

A 10 mil. film is cast from the resulting admixture and the cast film dried at 150 C. for 5 minutes in the absence of light. Specifically defined triangular and rectangular areas of the film are exposed to ultraviolet radiation for a period of 10 minutes. The film is then fixed in ammonium hydroxide solution for 5 minutes and then re-exposed over the entire film area to ultraviolet light for 30 minutes.

The triangular and rectangular areas are sharply defined after the fixing step and the 30-minute re-exposure does not noticeably affect either the produced image or the film.

EMMPLE III The value of the ammonia fixing step in the preparation of photographic images is illustrated in this example. Specifically defined triangular and rectangular areas of the film as prepared in Example II are exposed for 10 minutes to ultraviolet light. The triangular and rectangular areas are sharply defined indicating the effectiveness of the prepared film as a photographic film. On standing in the presence of room lighting, the film slowly changes to a light brown hue.

aqueous dispersions of this invention are demonstrated. 1" x 6" strips of cotton cloth are impregnated with various silver-containing aqueous dispersions of this invention. The impregnated cloths are dried in an oven at 135 C. for minutes and buried in warm greenhouse soil for a EXAMPLE IV 5 period of 17 days. The buried cloths are visually examined In this example, in the preparation of photographic for bacteria and fungus attack and tensile strengths film, the use of a silver-containing ethylene polymeric measured before and after soil burial. All tests are run composition when silver acetate is employed as the silver in triplicate with the results obtained in each test showing salt is illustrated. The following formulation is prepared: substantially no variation between the samples. Each of 6.0 ml. of a 0.1 molar silver acetate aqueous solution is the cloths buried contained about 0.082 grams of solid bi d ith 6 1 of ammonium hydroxide polymer. The formulation used for the impregnating solutrated); to the admixture is added 35 ml. of the waterliOIlis as follows: insoluble, self-emulsifiable ethylene-methyl acrylate aqueof Salt solution (Q1 001 molar as indioatcd ous dispersion of Example I. A laminated structure is below), prepared by coating Mylar film with the above-described 6.0 ammonium hydroxide (concentrated), aqueous dispersion and drying the Coated Mylar film at 35 ml. of the ethylene-methyl acrylate aqueous dispersion 150 C. A commercial developer (Eastman X-Ray De- ()f-Examplc I, veloper E4070A) is added to thfi hghtexposed Coaied The particular salts employed and the results obtained Mylar film and the fi thereafter fixd by contactmg are presented below in Table II. Run 1 is a control run in Wlth an 'flqueous sQlutlon of ammoma- The resultant m that no salt is employed in the aqueous dispersion emls yellowish brown 111 colorployed in impregnating the cotton cloth. in Runs 3, 5, 7 Similar results are Obtained When this Procedure is and 9 the prepared silver-containing aqueous dispersions peated with the exception that bond paper is coated with r o t ted with th photographic developer of E the polymeric composition contained in the aqueous disample IV prior to being placed in contact with the cotton persion. cloth.

TABLE III Tensile strength, Visual observation after soil burial p.s.i.

Ru Bacteria Fungus Before After No Salt solution Appearance attack tack burial burial 1 Control Good Trace Trace 6,150 3,140 2 .1 M AgNO:i Very good None "do 5,380 4, 950 3 .lMAgNOi Poor Massive..." Modcrate 5, 040 1,500 .01 M AgN0i. Very good None Trace 5,600 4,650 01MAgNO3 loor Massive..." Massive"... 5,160 1,000

Goo None 5,030

Poor Massrv 1,170

. P0021. Massiv 1,300 M OuSOn. Very poor do 000 .01 M OnSOi do .do do 5, 270 1,400

EXAMPLE V The procedure of Example IV is repeated with the exception that the silver salt employed is silver fiouride and, as in Example IV, the prepared aqueous dispersion containing silver ion is coated on the Mylar. The resultant film after fixing with ammonia is yellowish-brown in color.

EXAMPLE VI The procedure in Example IV is repeated with the exception that the nitrogenous base employed is prepared by adding grams of a 25 weight percent aqueous methyl amine solution to 10 ml. of water. 6 ml. of this prepared solution is then employed in place of the 6.0 ml. ammonium hydroxide solution of Example IV. The silvercontaining polymeric composition is cast on Mylar and dried as in 'Example IV. The commercial developer of Example IV is added to the light-exposed coated Mylar film. There is a uniform darkening of the film upon being contacted with the developer with no change after the developer-contacted film is placed in ammonium hydroxide.

EXAMPIJE VII The procedure of Example VI is repeated with the exception that the nitrogenous base employed comprises 9.0 grams of ethylene diamine diluted 'with 10 ml. of Water. 6.0 ml. of this prepared solution is then employed in the formulation of Example VI. The coated Mylar film darkens when immersed in the developer with no additional change effected when the developer-contacted film is immersed in ammonium hydroxide.

EXAMPLE VIII In this example the bacteria and fungus resistance of cotton cloth when coated with the silver-containing From the above it is evident that the copper salt is ineffective in producing a coating which resists bacteria and fungus attack. It is also readily apparent that when the silver salt is reduced to metallic silver as in Runs 3, 5, 7 and 9 by the action of the photographic developer the effectiveness of the impregnating composition is substantially destroyed. Runs 2, 4, 6 and 8 illustrate that the presence of silver as the silver ion in the solution employed to impregnate the cotton cloth is highly etfective in resisting bacteria and fungus attack.

Although the invention has been described 'with reference to specific materials, embodiments and details, various modifications and changes, within the scope of this invention, will be apparent to one skilled in the art and are contemplated to be embraced in the invention.

What is claimed is:

1. An aqueous dispersion of a water-insoluble, selfemulsifiable ethylene polymer containing silver, said ethylene polymer comprising units (a) and units (b) as hereinafter defined and, optionally one of the hereafter defined tollowing units (c) and units (d):

9 wherein R is selected from the group consisting of hydrogen and hydrocarbon groups, R is selected from the group consisting of hydrogen and alkali metal cations, R and R are independently selected from the group consisting of hydrogen, hydrocarbon groups, and hydroxy alkyl groups, and R is a hydrocarbon group, the concentration of the total of units (b), (c) and (d) being in the range of 0.01 to about 0.5 mol per mol of contained ethylene, and at least 10 mol percent of the acrylate groups being in carboxylate salt form.

2. The aqueous dispersion of claim 1 wherein said silver is present as the silver ion.

3. A composition comprising a Water-insoluble, selfemulsifiable, ethylene polymer containing silver ions, said ethylene polymer comprising units (a) and units (b) as hereinafter defined and, optionally one of the hereafter defined following units (c) and units (d):

wherein R is selected from the group consisting of hydrogen and hydrocarbon groups, R is selected from the group consisting of hydrogen and alkali metal cations, R and R are independently selected from the group consisting of hydrogen, hydrocarbon groups, and hydroxy alkyl groups, and R is a hydrocarbon group, the concentration of the total of units (b), (c) and (d) being in the range of 0.0 1 to about 0.5 mol per mole of contained ethylene, and at least 10 mol percent of the acrylate groups being in carboxylate salt form.

4. A film of the composition of claim 3.

5. A process which comprises forming an aqueous mixture of a silver salt and a nitrogenous base, and introducing the resultant aqueous mixture into an aqueous dispersion of a Water-insoluble, but self-emulsifiable ethylene polymer, said ethylene polymer comprising units (a) and units (b) as hereinafter defined and, optionally one of the hereafter defined following units and units (d):

at least 10 mol percent of the acrylate groups being in carboxylate salt form.

6. The process of claim 5 to include casting a film from the said aqueous mixture.

7. The process of claim 6 to include the step of exposing the cast film to light.

8. The process of claim 7 wherein said silver salt is selected from the group consisting of silver acetate, silver nitrate and silver fluoride.

9. The process of claim 8 wherein said nitrogenous base is ammonia.

10. The process of claim 7 to include the step of thereafter fixing the exposed film by contacting with ammonia.

11. A process which comprises contacting a strongly acidic cation exchange resin charged with silver ions with an aqueous dispersion of a water-insoluble, but selfemulsifiable ethylene polymer in the presence of a nitrog enous base, and recovering therefrom a shelf-stable aqueous dispersion of a Water-insoluble, self-emulsifiiable ethylene polymer containing silver, the ethylene polymer brought into contact with the strongly acidic cation exchange resin charged with silver ions comprising units (a) and units (b) as hereinafter defined and, optionally one of the hereafter defined following units (c) and units (d):

wherein R is selected from the group consisting of hydrogen and hydrocarbon groups, R is selected from the group consisting of hydrogen and alkali metal cations, R and R are independently selected from the group consisting of hydrogen, hydrocarbon groups, and hydroxy alkyl groups, and R is a hydrocarbon group, the concentration of the total of units (b), (c) and ((1) being in the range of 0.01 to about 0.5 mol per mol of contained ethylene, and at least 10 mol percent of the acrylate groups being in carboxylate salt form.

12. A process which comprises coating a substrate with a Water-insoluble, but self-emulsifiable ethylene polymer composition containing silver ions, and thereafter exposing the substrate to bactericidal and/or fungicidal attack, said ethylene polymer comprising units (a) and units (b) as hereinafter defined and, optionally one of the hereafter defined following units (c) and units (d):

sisting of hydrogen, hydrocarbon groups, and hydroxy alkyl groups, and R is a hydrocarbon group, the concentration of the total of units (b), (c) and (d) being in the range of 0.01 to about 0.5 mol per mol of contained ethylene, and at least 10 mol percent of the acrylate groups being in carboxylate salt form.

13. The process of claim 12 wherein said substrate is selected from the group consisting of wood and cotton.

14. A process which comprises forming an aqueous mixture of a silver salt selected from the group consisting of silver acetate, silver nitrate, silver chloride and silver phosphate with ammonia, introducing the resultant aqueous mixture into an aqueous dispersion of a Waterinsoluble, but self-emulsifiable ethylene polymer, coating a substrate with the resultant silver-containing polymeric aqueous dispersion, and thereafter exposing the coated substrate to bactericidal and/or fungicidal attack, said ethylene polymer contacted with said resultant aqueous mixture comprising units (a) and units (b) as hereinafter defined and, optionally one of the hereafter defined following units and units (d):

wherein R is selected from the group consisting of hydrogen and hydrocarbon groups, R is selected from the group consisting of hydrogen and alkali metal cations,

R and R are independently selected from the group consisting of hydrogen, hydrocarbon groups, and hydroxy alkyl groups, and R is a hydrocarbon group, the concentration of the total of units (b), (c) and (d) being in the range of 0.01 to about 0.5 mol per mol of contained ethylene, and at least 10 mol percent of the acrylate groups being in carboxylate salt form.

15. The aqueous dispersion of claim 1 wherein said ethylene polymer contains units (c) and units (d) and wherein R and R are hydrogen.

16. The aqueous dispersion of claim 15 wherein R is a methyl group.

17. The process of claim 5 wherein said silver salt is selected from the group consisting of silver chloride, silver sulfate, silver nitrate, silver acetate, silver fluoride, silver phosphate and silver chromate.

18. The process of claim 17 wherein said nitrogenous base is selected from the group consisting of ammonia, primary and secondary amines and diamines.

19. The process of claim 11 wherein said nitrogenous base is selected from the group consisting of ammonia, primary and secondary amines and diamines.

References Cited UNITED STATES PATENTS 2,808,388 10/1957 Hellman 96-114X 2,848,434 8/1958 Hellman 96-114X 3,249,570 5/1966 Potts et al. 260-296 3,397,988 8/ 1968 Van Paesschen et al. 96-114 OTHER REFERENCES Mees, C. E., The Theory of the Photographic Process, 1949, pp. 6, 7.

Websters Third New International Dictionary, 1965, p. 1572.

RONALD H. SMITH, Primary Examiner US. Cl. X.R.

@2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3556.795 I Dated March 16. 1971 IIWQMMTS) Richard H1 Huqhes, Bert H. Clampitt, Harry D. Anspo:

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 8, just after line 61, formula "a" was left out. It should read -(a) CH CH Column 10, just after line 24 formula "a" was left out. It should read (a) CH CH Signed and sealed this 25th day of May 1971.

EDHARD I-I.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

